Tires are typically prepared of treads of elastomer based rubber compositions which are conventionally carbon black reinforced. Sometimes tire tread rubber compositions may also be reinforced with silica by utilizing a combination of individual silica and carbon black particles. Typically the silica is a precipitated silica.
Often coupling agents are used with precipitated silica to assist in its reinforcement of elastomers with which the silica is mixed. Utilization of silica couplers for such purpose is well known to those skilled in such art.
It is appreciated that electrical conductivity of a rubber composition is reduced when silica replaces a portion of more conventional carbon black for reinforcing rubber compositions
In the description of this invention, the term "phr" where used herein, and according to conventional practice, refers to "parts of a respective material per 100 parts by weight of rubber, or elastomer".
In the description of this invention, the terms "rubber" and "elastomer" if used herein, may be used interchangeably, unless otherwise prescribed. The terms "rubber composition", "compounded rubber" and "rubber compound", if used herein, are used interchangeably to refer to "rubber which has been blended or mixed with various ingredients and materials" and such terms are well known to those having skill in the rubber mixing or rubber compounding art.